This compat property sole function is to prevent the device from being
instantiated. Instead of requiring an extra compat property, check if
fw_cfg has DMA enabled.
fw_cfg is a built-in device that is initialized very early by the
machine init code. We have at least one other device that also
assumes fw_cfg_find() can be safely used on realize: pvpanic.
This has the additional benefit of handling other cases properly, like:
$ qemu-system-x86_64 -device vmgenid -machine none
qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in
fw_cfg, which this machine type does not provide
$ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.9 -global
fw_cfg.dma_enabled=off
qemu-system-x86_64: -device vmgenid: vmgenid requires DMA write support in
fw_cfg, which this machine type does not provide
$ qemu-system-x86_64 -device vmgenid -machine pc-i440fx-2.6 -global
fw_cfg.dma_enabled=on
[boots normally]
Suggested-by: Eduardo Habkost <ehabk...@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Reviewed-by: Eduardo Habkost <ehabk...@redhat.com>
Reviewed-by: Ben Warren <b...@skyportsystems.com>
Reviewed-by: Laszlo Ersek <ler...@redhat.com>
---
include/hw/acpi/bios-linker-loader.h | 2 ++
include/hw/compat.h | 4 ----
hw/acpi/bios-linker-loader.c | 10 ++++++++++
hw/acpi/vmgenid.c | 9 +--------
4 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/include/hw/acpi/bios-linker-loader.h
b/include/hw/acpi/bios-linker-loader.h
index efe17b0b9c..a711dbced8 100644
--- a/include/hw/acpi/bios-linker-loader.h
+++ b/include/hw/acpi/bios-linker-loader.h
@@ -7,6 +7,8 @@ typedef struct BIOSLinker {
GArray *file_list;
} BIOSLinker;
+bool bios_linker_loader_can_write_pointer(void);
+
BIOSLinker *bios_linker_loader_init(void);
void bios_linker_loader_alloc(BIOSLinker *linker,
diff --git a/include/hw/compat.h b/include/hw/compat.h
index 08f36004da..f414786604 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -150,10 +150,6 @@
.driver = "fw_cfg_io",\
.property = "dma_enabled",\
.value = "off",\
- },{\
- .driver = "vmgenid",\
- .property = "x-write-pointer-available",\
- .value = "off",\
},
#define HW_COMPAT_2_3 \
diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c
index 046183a0f1..d16b8bbcb1 100644
--- a/hw/acpi/bios-linker-loader.c
+++ b/hw/acpi/bios-linker-loader.c
@@ -168,6 +168,16 @@ bios_linker_find_file(const BIOSLinker *linker, const char
*name)
return NULL;
}
+/*
+ * board code must realize fw_cfg first, as a fixed device, before
+ * another device realize function call bios_linker_loader_can_write_pointer()
+ */
+bool bios_linker_loader_can_write_pointer(void)
+{
+ FWCfgState *fw_cfg = fw_cfg_find();
+ return fw_cfg && fw_cfg_dma_enabled(fw_cfg);
+}
+
/*
* bios_linker_loader_alloc: ask guest to load file into guest memory.
*
diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c
index a32b847fe0..ab5da293fd 100644
--- a/hw/acpi/vmgenid.c
+++ b/hw/acpi/vmgenid.c
@@ -205,17 +205,11 @@ static void vmgenid_handle_reset(void *opaque)
memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le));
}
-static Property vmgenid_properties[] = {
- DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState,
- write_pointer_available, true),
- DEFINE_PROP_END_OF_LIST(),
-};
-
static void vmgenid_realize(DeviceState *dev, Error **errp)
{
VmGenIdState *vms = VMGENID(dev);
- if (!vms->write_pointer_available) {
+ if (!bios_linker_loader_can_write_pointer()) {
error_setg(errp, "%s requires DMA write support in fw_cfg, "
"which this machine type does not provide", VMGENID_DEVICE);
return;
@@ -239,7 +233,6 @@ static void vmgenid_device_class_init(ObjectClass *klass,
void *data)
dc->vmsd = &vmstate_vmgenid;
dc->realize = vmgenid_realize;
dc->hotpluggable = false;
- dc->props = vmgenid_properties;
object_class_property_add_str(klass, VMGENID_GUID, NULL,
vmgenid_set_guid, NULL);
--
2.13.1.395.gf7b71de06
